Commonly used systems for lashing containers are known from EP 2 650 171 A1 and DE 202 03 067 U1. Such container lashing systems typically comprise a lashing rod and a turnbuckle. The turnbuckle comprises a first connection part and a second connection part for connecting the turnbuckle respectively to a first end of the lashing rod and to a container transport vehicle, such as for example a ship, a barge or other floating vehicle, or a train. The first connection part and the second connection part of the turnbuckle are connected to each other by two parallel beams which form the main body of the turnbuckle. The lashing rod is provided at a first end for being connected to the turnbuckle and at a second end for being connected to an intermodal freight container or any other type of suitable container on the container transport vehicle.
The first connection part of the turnbuckle comprises a locating seat arranged at a first end of the lashing rod. This locating seat comprises a semi-circular opening behind which locating rings, protruding from the lashing rod at its first end, may be seated for connecting the lashing rod to the turnbuckle. Multiple locating rings are arranged on the lashing rod at equals distances from each other, such that the overall length of the container lashing system formed by the connected lashing rod and turnbuckle may be roughly set by seating different locating rings behind the locating seat. To strengthen the connection between the lashing rod and the turnbuckle multiple locating seats may be provided on the turnbuckle at the same distances from each other as the locating rings on the lashing rod.
The second connection part of the turnbuckle comprises a threaded rod which is arranged through a threaded opening at the second end of the turnbuckle. At one end the threaded rod is provided with a connection element, for example a buckle or a hook, for connecting, either directly or via one or more intermediate lashing rods, to a container transport vehicle, for example for connecting to a deck of a ship or a lashing bridge on a deck of a ship. The threaded rod may be screwed through the threaded opening for precisely controlling the overall length of the container lashing system formed by the connected lashing rod and turnbuckle and thereby tensioning the lashing rod to achieve lashing of the container. When the lashing rod and the turnbuckle are connected to each other and respectively to the shipping container and to the container transport vehicle, the screwing of the threaded rod through the threaded opening is achieved by rotating the turnbuckle around its longitudinal axis. Initially, this may be done by hand, but when the tension on the lashing rod increases a lever tool is used.
Rotating the turnbuckle clockwise increases the tension, securing the container to the ship. Rotating the turnbuckle counterclockwise decreases the tension until the lashing rod and turnbuckle are disconnected. For lashing the container, the turnbuckle is initially rotated by hand. However, when the tension on the turnbuckle increases and manual rotation is no longer possible, then a lever tool is used to rotate the turnbuckle further until the required tension is reached. The lever tool is also used during unlashing for removing the lashing rods. They are used for rotating the turnbuckle until the tension has sufficiently decreased for further rotating the turnbuckle by hand.
The process of lashing containers with such container lashing systems has however the disadvantage that it is time-consuming and not without danger for the person rotating the turnbuckle.
Sufficiently tensioning the lashing rod takes some time because rotating the turnbuckle needs to be done manually and requires a significant amount of force. Rotating the turnbuckle is also tiresome for the person rotating the turnbuckle, such that periods of rest need to be taken into account.
The person rotating the turnbuckle also has to take care that his hands are not caught between the lashing rod, the turnbuckle and/or the lever tool while operating the turnbuckle, which might cause injury.
When using lever tools, workers have to put their body weight into the movement which makes them very vulnerable for accidents. If they push too hard and the turnbuckle suddenly loosens they risk smashing their arms and/or fingers onto parts of the container lashing system or against the container transport vehicle. If they pull too hard they can even fall or trip. In both cases, dangerous situations may quickly arise. Constant pushing and pulling movements may cause injury, such as for example aching muscles in arms and/or shoulders.